超声波制备介孔结构的氮掺杂TiO_2纳米晶及其可见光催化性能(英文)

Ultrasonic fabrication of N‐doped TiO_2 nanocrystals with mesoporous structure and enhanced visible light photocatalytic activity

采用超声波辐射法制备了具有介孔结构的高浓度氮掺杂TiO2纳米晶(N/TiO2).采用N2物理吸附、X射线粉末衍射、X射线光电子能谱、透射电镜、光致发光谱和紫外-可见漫反射光谱等手段对N/TiO2进行了表征.以波长为400~660nm的可见光为光源,以水体污染物邻苯二甲酸二甲酯为降解对象,考察了不同制备方法对N/TiO2光催化性能的影响.结果表明,超声波辐射使氮掺杂浓度提高了2.2倍,该法制备的N/TiO2同时具有较好的介孔结构,表现了更高的光催化降解邻苯二甲酸二甲酯的活性.其活性提高的主要原因是N/TiO2含有更高浓度的氮和对可见光具有更强的吸收能力.

An ultrasonic method was developed to fabricate novel mesoporous TiO2 nanocrystals doped with a high concentration of N (N/TiO2 ). The nanocrystals were characterized by physicochemical methods including N2 physical adsorption/desorption, X‐ray diffraction, X‐ray photoelectron spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, and UV‐Vis diffuse reflectance spectroscopy. The photocatalytic degradation of dimethyl phthalate, a hazardous chemical in water, by the prepared N/TiO2 nanocrystals under visible light irradiation (400 660 nm) was investigated. The results show that N‐doping efficiency under ultrasonic irradiation is 3.2 times higher than under typical conditions, and the produced TiO2 nanocrystals have mesoporous structure. N/TiO2 fabricated under ultrasound exhibited much higher efficiency for the degradation of dimethyl phthalate than that prepared under typical conditions. The high photocatalytic degradation activity of N/TiO2 fabricated under ultrasound is mainly attributed to its high N content effectively increasing its ability to absorb visible light.